Application Of μ-oxo-bis[Tetra-phenyl Porphyrinatoiron] Complex For Cotton Fabric Hydrogen Peroxide Bleaching At Low Temperature

Conventional bleaching of cotton fabric with hydrogen peroxide is conducted at high temperature and severe alkaline conditions,which usually cause high energy consumption and fiber strength damage extremely.Therefore,researchers of dyeing and finishing industry commit to exploit innovative low-temperature catalytic bleaching system.μ-Oxo-bis[tetra-phenyl porphyrinatoiron]complex（[TPPFe]₂O）,which presents relatively higher catalytic and selective properties in mild conditions,is one of the potent catalysts to reduce the temperature in bleaching process.In this paper,the synthesis of[TPPFe]₂O and its catalytic properties for hydrogen dioxide was investigated.Then,establishing low temperature and high efficient[TPPFe]₂O/H₂O₂ bleaching system,which provided a new friendly and energy saving method.Firstly,the synthesis of[TPPFe]₂O was studied.Its synthetic routes and methods were discussed and the synthesis process was optimized after the research effecting factors on yield and trial.The new method will improve the traditional one.The structure and yield of the product were analyzed by FTIR,XPS and EA.The results show that:the optimal process of the new synthesis method is as follows:the ratio of tetrapheylporphyrin to FeSO₄·7H₂O is 1:6,the reaction time was 10 hours in 130℃.The yield reached to 93%.The novel synthesis method was simply to operate and compose highly productivity in conducted in neutrality condition.Then,[TPPFe]₂O/H₂O₂ bleaching system with low temperature was constructed.The catalytic property of[TPPFe]₂O for hydrogen peroxide decomposition was investigated by the permanganate titration.The results show that:in lower temperature and shorter time,the ratio of H₂O₂ decomposition[TPPFe]₂O/H₂O₂ bleaching system,which is 11.5%higher than traditional system and 10.5%higher than TAED activated system.It proves that[TPPFe]₂O takes on excellent catalytic activity.Finally,the application of[TPPFe]₂O in low temperature bleaching of cotton fabric and the mechanism of bleaching were investigated.Single factor and orthogonal test was used to study the influences of every process factors for bleaching results,then optimized them.The results show that:the optimum conditions were metal complex 0.003g/L,30%H₂O₂ 1.8 g/L,stabilizer0.5 g/L at 70℃and pH value 11 for 45 min.The fabric bleached with optimal process achieves the whiteness index to 73.6%,and the breaking strength retention is 94.5%.Compared to the results of conventional bleaching method,when receiving the similar whiteness,the temperature decreased 20℃,breaking strength retention increased 13.5%,time was reduced 15 min.The results present that[TPPFe]₂O not only has a superiority on energy saving but also the bleaching sustainability of fabric properties.